Garden room brick/block advice please

[Marlboro2026]

Greetings :
I am replacing an old asbestos garage with a garden room. The footprint is sizeable 30m2, within permitted development and contacted my local planning regs office already. 

I decided I would hire each trade individually, I have a limited budget for this project. 

My dad was a sparky and I lost him last year. Whilst a sparky, he would turn his hand to lots of things at home and was my go to person for everything, I am a pen pusher and miss him. I am hoping for some guidance as to what stages I should be doing things and some recommendations on the build.
It will be used for storage and a home office. Electricity, no plumbing.

I hired a digger who has demolished what was there and he will move on to the next stages :
Footings 450mm x 450 deep & wide
Solid floor / type 1 hardcore + 150mm concrete with mesh + 50mm screed

The next step is block & brick, I think some form of insulation between the two?
If the height is 2.5m, width 7m and depth 6m, how many engineered bricks do I need, normal bricks and blocks?
The guy who is doing my foundations initially told me he has a couple of bricky friends and it would cost £80m2, it then became £120m2 and would take 2
months to build because brickies can only lay a certain number of courses for stability or it would collapse. I Googled this and accept it is now winter, but 2 metres at a time seemed acceptable? Since the height is only 2.5 metres, I am confused.

Do I engage a roofer at the same time as a bricklayer or once the walls are complete or nearly complete, I am not sure if technically, they somehow work in unison?
The door/window fitter, is this something the bricklayer would do?

I am going for a flat roof, what sort of wooden beams do I need?
EPDM, GRP or felt roofing and what is involved and what sort of materials should I be looking at sourcing?

Attached is an AI generated photo of what I would like to achieve.

Appreciate some guidance. I am not cheap, but my funds are limited so I am trying to get a good build for a fair price.
Many thanks in advance.

[Onoff]

I'd think about insulation under the floor, like 150mm min. If you're laying a concrete slab then why not incorporate UFH pipes now even if you never use them? 

 

You'll want the walls insulated too. Pointless not too. 

 

At that size I'd have put a trench in with soil & water pipes coming up through the slab as future proofing. Decide on your plan where you might later on want a WC / shower room. 

[gaz_moose]

its 60 bricks per square meter of single skin wall.

10 blocks per square meter of single skin wall.

you just need to ask the roofer to build you a roof and not worry about beam thickness etc.. as that's what your paying him for. 

it would be worth asking the bricky about bricks/blocks as they will get a deal at the suppliers. 

 

[torre]

If all you've done so far is demolition, I'd take a pause for breath while you do the sort of research you're starting here.

 

Managing the job yourself should save costs but not without either more experience or a lot more up front planning - definitely not if £80/m2 suddenly jumps to £120/m2 (was that labour only or inc materials?). It might even be worth getting two or three quotes before deciding how much you might actually save, versus the stress and probably much longer build time. A builder may give you some advice on making the most of this in terms of running services etc

 

Check your sizes as 6m x 7m externally will be larger than 30m2 of internal floor area, which would mean you need to comply with building regulations.

 

Even without building regs, insulate everywhere - this will be quite an expensive build so you want it as usable as possible.

 

For a flat roof I think you can be 3m high within permitted development and you'll want to be close to that as a warm roof takes a fair amount off your headroom.

 

(If you do get some quotes in I'd remove the nice raised beds from the render as while they look high end, they might suggest you've a high end budget too)

[gaz_moose]

The brick facia boards are probably why the labour charges went up. 

[Mr Punter]

3 hours ago, gaz_moose said:

The brick facia boards are probably why the labour charges went up. 

 

In reality they won't happen as not practical / cost effective.

[markc]

To keep cost down, Keep It Simple. If you want the brick facia, why not double skin blockwork and front / fascia using cladding although the design / render must be above 3m high so you will probably have to lose the step and thin down the roof / facia.

definitely insulation under the slab and you might as well do walls while doing blockwork - or blown beads later on.